1. Field of the Invention
The invention relates to photo-optical keyboards. More specifically, the invention relates to an improved keyboard housing and keys for protecting against liquid and debris spills.
2. Description of the Prior Art
Liquid spillage and debris falling into a keyboard are a serious problem. Liquid will normally drain down around the keystems and into the keyboard structure itself. This may be damaging to photo-optical keyboards since the liquid may get into the optical channels and present a blockage of light. Up to the present time there has been no satisfactory means of protecting against such spills and debris. Most keyboard manufacturers use some sort of optional plastic rainshield apron or boot that fits under the keycaps and serves to keep liquids out of the workings of the keyboard.
The present invention uses an umbrella shaped keyhead which overlaps recesses in the keyboard to catch spills and debris. The prior art shows umbrella shaped keyheads, for example in U.S. Pat. Nos. 3,787,837, 3,818,485, and 3,964,593. However, these references do not address the problem of spills or debris and do not disclose any means of catching a spill on a keyboard.